Solar Install: what would you change

[canada_rokzz]

I’m going to do a small solar install on my 5th wheel, and I am curious what you would change about your current setup. What did you do that was wrong, not good enough or just a minor annoyance.

My plan is two 100w semi flexible 12v panels wired in series to an MPPT controller charging a 200 amp hr battery bank. We will only be boondocking a few weekends a year, and beyond the fridge and lights we will be running a TV/DVD combo in the evening for our little monsters (5 and 2 year old boys). I think this setup should keep us charged enough for 4-5 days which is about the max of our water storage for my family. We are not great at water conservation in the camper...

Thoughts?
Info?
Thanks!

[Almot]

canada_rokzz wrote:
I’m going to do a small solar install on my 5th wheel, and I am curious what you would change about your current setup. What did you do that was wrong, not good enough or just a minor annoyance.

My plan is two 100w semi flexible 12v panels wired in series to an MPPT controller

Hold it right there 🙂
Don't know whether I'll add something of value after some big guns said their piece, I didn't read all 4 pages, but...

1) There is not much need in good quality $$$ MPPT with mere 2*100 panels. OTH, low quality MPPT is not worth buying.
$50 Grape PWM from Home Depot will exceed your requirements, it will be rich in features and likely cheaper than a comparable MPPT. 2*100W can be wired in parallel with PWM, cable gauge may remain the same #10 (or you can get #8 MC4 if you like, it connects to standard MC4 panel fittings). On your small 2*100W system you will gain very little energy with MPPT , getting more panel wattage will work better.
Disclaimer: I have MPPT - but I DO need it, my panels are 500W total.

2) There is probably no benefit in semi-flexible panel compared to rigid, if your roof is the usual particle board.

3) What others said - get more solar wattage than you think you need. 200W in Northern Canada is very, very little.

4) To answer your question - No, I didn't do anything that was "wrong or annoyance or not good enough". No regrets about getting 30A MPPT Rogue - the best 30A MPPT available at that time. Thanks again to Don Piano for pointing me out this one. 500W array is "good enough" where I am, but it could've been better. You can't have too much solar.

What I would change in my solar... I would get better batteries than Chinese-made UPG. I would also get 100-200W more solar wattage, for total 600-700W, rather than my current 500W. (Though, this in turn would lead to bigger/costlier MPPT than my current 30A).

[pianotuna]

Hi,

Not quite so simple.

My panels are no longer made and have diodes between each and every cell.

The input voltage is 33 so I needs must have an MPPT charge controller.

Where I reside it gets down to -40 and up to +40 c (104 f) so temperature adjusted charging is a MUST DO.

The OEM solar wiring is #10 so boosting amperage would require new heavier gauge wire.

If I were going to start over it would be to go to 1600 watts at a cost of $2 per watt on the solar side--and move to 48 volts, which means replacing the inverter/charger. I'd add a 48 volt dc to 12 volt dc converter for the "house" loads on the RV.

That is about $7000.00 plus installation costs.

allen8106 wrote:

pianotuna wrote:
Hi,

The one misstep I made was to max out the capacity of the Blue Sky charge controller. I'd love to add more panels--but I can't without replacing the controller.

You can just "add" a smaller second controller for a minimal cost.

[allen8106]

Chad Heiser wrote:

allen8106 wrote:
For only two panels I would wire them in parallel and forget the MPPT controller.

My recommendations:
Tr-Star TS-45 Controller
Magnum MS2012 inverter
Bogart TM-2030 Battery Monitor
2 Crown 6v batteries wired in series

These are good recommendations. However, if going with a Magnum inverter, I would use the Magnum BMK battery monitor instead of the Bogart Trimetric. They are both good, but the Magnum has more options and integrates with the inverter remote (so less to install).

Crown batteries are very good, but if you are looking for a less expensive quality battery, take a look at Fullriver.

Chad, good points sir. I actually have both the TM-2030 and the Magnum MC-RC50 remote because it allows me the option of turning the inverter off remotely if I wish.

[allen8106]

pianotuna wrote:
Hi,

The one misstep I made was to max out the capacity of the Blue Sky charge controller. I'd love to add more panels--but I can't without replacing the controller.

You can just "add" a smaller second controller for a minimal cost.

[carl2591]

check out teh airstream forums airforums.com as a lot of folks use a 3m double stick tape to attach feet to roof for solar panels and when installed properly they will not come off running down the road.

I would put some on front angle, the middle angle and couple on the rear which is a differnt angle. that way you get sun all the day.

ktmrfs wrote:

canada_rokzz wrote:
I’m not going to install tilting or ridged panels, as I’m not interested in climbing on my roof. They will be flexible, and glued to the roof. That said, this is my roof line and I’m not sure what my best positioning would be?

what kind of roof do you have? if it is a rubber roof glued down, I'd recomend NOT gluing it to the roof. that roof material dAoes usually not have a very high shear resistance and I can see the panel coming off and damaging the roof.

And if you do go this way, be careful of what adhesive you use. use of the wrong adhesive can end up destroying the roof material.

[carl2591]

happens all the time.. if you add more panels just add another CC and hook up to battery.. they don't care where the power comes from.

a good lower cost PWM controller like the bogart 2030 is a good way to go up to about 400 watts.

pianotuna wrote:
Hi,

The one misstep I made was to max out the capacity of the Blue Sky charge controller. I'd love to add more panels--but I can't without replacing the controller.

[Chad_Heiser]

An MPPT controller will always outperform a PWM controller (this isn’t an absolute, but close enough for the purposes we are discussing). However, the cost difference between the two should be weighed into the decision. If your panels are within the voltage range of a PWM controller and you plan to run the panels in parallel only, then a PWM controller may be more cost effective on a budget.

I personally always size a controller bigger (within reason) than is needed for systems I design. It is more cost effective to spend a little more up front for a controller capable of growing with your needs than it is to by a smaller/less capable controller up front and then have to buy a completely different controller later in order to expand. I apply this same reasoning to wire size in my systems. Spend a little more up front to allow for growth rather than having to rip everything out and start over when you want to expand. Of course everyone has a budget that has to be met, so all of this has to be weighed against that to make an informed decision.

[pianotuna]

Hi,

Yes, so long as the new panels match the old, and do not exceed the capacity of the charge controller.

There are just two times that MPPT makes sense. If you have used up all the roof real estate and you wish to harvest every erg of power then go MPPT. OR if high voltage panels have been chosen.

canada_rokzz wrote:

allen8106 wrote:
For only two panels I would wire them in parallel and forget the MPPT controller.

So when I spring for two more panels will a PWM controller still be cool?

[canada_rokzz]

allen8106 wrote:
For only two panels I would wire them in parallel and forget the MPPT controller.

So when I spring for two more panels will a PWM controller still be cool?

[Chad_Heiser]

allen8106 wrote:
For only two panels I would wire them in parallel and forget the MPPT controller.

My recommendations:
Tr-Star TS-45 Controller
Magnum MS2012 inverter
Bogart TM-2030 Battery Monitor
2 Crown 6v batteries wired in series

These are good recommendations. However, if going with a Magnum inverter, I would use the Magnum BMK battery monitor instead of the Bogart Trimetric. They are both good, but the Magnum has more options and integrates with the inverter remote (so less to install).

Crown batteries are very good, but if you are looking for a less expensive quality battery, take a look at Fullriver.

[allen8106]

For only two panels I would wire them in parallel and forget the MPPT controller.

My recommendations:
Tr-Star TS-45 Controller
Magnum MS2012 inverter
Bogart TM-2030 Battery Monitor
2 Crown 6v batteries wired in series

[Vintage465]

I had my panels and controller installed at the dealer I purchased the trailer. I have 2 each 150w panels and wish I had three panels for the less than stellar (clear) day. I also wish they had not placed the panel right over the master bed. I will wind up re-arranging the panels, adding one and then putting a Fantastic Vent w/remote over my bed. But I will say that I seem to have plenty of charging abilities to my two 6v Interstate Batteries.

[canada_rokzz]

ktmrfs wrote:
what kind of roof do you have?

It is a rubber roof, and sheer was something I gave no Consideration. Looks like I may have to. Thanks!

[ktmrfs]

canada_rokzz wrote:
I’m not going to install tilting or ridged panels, as I’m not interested in climbing on my roof. They will be flexible, and glued to the roof. That said, this is my roof line and I’m not sure what my best positioning would be?

what kind of roof do you have? if it is a rubber roof glued down, I'd recomend NOT gluing it to the roof. that roof material dAoes usually not have a very high shear resistance and I can see the panel coming off and damaging the roof.

And if you do go this way, be careful of what adhesive you use. use of the wrong adhesive can end up destroying the roof material.